They wanted to build a new international revolutionary movement against the slaughter.

Lenin argued that the capitalists’ war was appalling, but represented an opportunity for revolutionaries and the working class.

He went on to say that to be effective against war it was necessary to go beyond pacifism and argue for a revolution to smash the system that creates war.

Lenin argued that socialists should call on workers to turn the war into a civil war against their own rulers.

He said that revolutionaries needed to argue with soldiers to not just lay down their weapons, but turn them on their rulers.

The Bolsheviks and Lenin did not win all of their demands.

But the outcome of the Kienthal conference was significantly more positive than Zimmerwald, at which delegates had agreed only to pacifist opposition to war.

The manifesto that was adopted stated, “There will be further intensification of the struggle against war and imperialism as a consequence of the ruination and suffering brought on by the calamities of this imperialist age.”

The manifesto also strongly criticised the Second International’s support for the war.

It stated that the only way to deliver a world without war was through the working class taking power.

A hundred years on, capitalism still produces the horrors of war.

They will not be eliminated until the system that produces them is overthrown.